Table 1 Value to biologists of using these behavioral, physiological, and ecological sensors on their electronic tags
Type | Property | Sensor | Value to biologist | Advantage/disadvantage |
|---|---|---|---|---|
Behavioral | Speed | Reed switch, inductive coil | Record swimming or flight speed | Can become jammed |
Hall effect probe | Record animal movements | Will not become jammed | ||
Piezoelectric transducer, MEMS | Record behavioral patterns, produce ethogram | Small and does not become jammed | ||
Tilt | Mercury switch | Monitor changes in posture | Â | |
Altitude, depth | MEMS altitude sensor | Record flight altitude | Works with low pressures | |
Strain gauge | Determine swimming depths | Works only with high pressures | ||
Direction | Optical heading sensor | Ascertain degree of directionality | Can become jammed | |
MEMS heading sensor | Monitor degree of directionality | Doesn’t become jammed | ||
Predation | Magnetic/electrode sensors | Identify time of feeding and prey | Â | |
Spawning | Ultrasonic detection | Identify time, environment, and behavior | Need to implant beacon in uterus of female | |
Sociality | Proximity sensor | Monitor social interactions | Transmitter/receiver needed | |
Physiological | Brain, muscular, or heart activity | Electrograms | Record diverse physiological responses | Electrodes can become bulky |
Gastric activity | pH sensor | Detect ingestion of prey | Â | |
Blood chemistry | Blood extractor | Monitor reproductive state or stress | Bulky with multiple syringes | |
Body temperature | Thermistor | Record endothermy or ectothermy | Small and durable | |
Environmental | Air/water irradiance | Photocell | Determine whether day or nighttime | Exhibit light history; are non-stationary over time |
Photodiode | Ascertain whether day or nighttime | No light history, stationary | ||
Air/water temperature | Thermistor | Record whether tropical, temperate, polar, air/water masses | Small and durable | |
Dissolved oxygen | Dissolved oxygen sensor | Identify aerobic/anaerobic envir. | Relatively bulky | |
Magnetic field | MEMS magnetic field sensor | Use to estimate latitude | Very small and accurate |